Thread supply device for textile machines

ABSTRACT

A thread supply device for a textile machine, comprising a thread drum which can be set in rotation and upon which there is tangentially wound a thread issuing from a storage bobbin in order to form an intermediate supply and from which drum the thread may be unwound vertically over a withdrawal rim of the drum and through a withdrawal eye assembly which is disposed coaxially to the drum and which comprises a cut-off eye which may be pivoted transversely to the thread passage due to spring action. A thread control element is stationarily arranged in the area of the path of the withdrawn thread adjacent the withdrawal rim, and against which thread control element the thread abuts laterally due to the withdrawal tension during positive thread supply. The cut-off eye is the first eye of the withdrawal eye assembly traversed by the thread after it has passed the withdrawal rim, and the spring load urges the cut-off eye away from the imaginary thread drum axis into the area below the withdrawal rim, into which area is also moved the point at which the thread leaves the withdrawal rim during a reduction of the withdrawal tension, whereby the thread tension assists the spring force in moving the cut-off eye into a deactivating or warning position.

United States Patent [1 1 [111 3,928,987

Jacobsson 1 Dec. 30, 1975 1 1 THREAD SUPPLY DEVICE FOR TEXTILE MACHINES 57 ABSTRACT lnvfimoll K1111 Ame Gunnal Jacobsson, A thread supply device for a textile machine, compris- Ulncehamn, Sweden ing a thread drum which can be set in rotation and [73] Assigneez Aktieboaget 1R0, Ulricehamn upon which there is tangentially wound a thread issu- Sweden ing from a storage bobbin in order to form an intermediate supply and from which drum the thread may be 1 1 Filed: g- 1974 unwound vertically over a withdrawal rim of the drum 211 Appl. No.: 495,880

Primary ExaminerLouis K. Rimrodt Attorney, Agent, or Firm-Woodhams, Blanchard and Flynn and through a withdrawal eye assembly which is disposed coaxially to the drum and which comprises a cut-off eye which may be pivoted transversely to the thread passage due to spring action. A thread control element is stationarily arranged in the area of the path of the withdrawn thread adjacent the withdrawal rim, and against which thread control element the thread abuts laterally due to the withdrawal tension during positive thread supply. The cut-off eye is the first eye of the withdrawal eye assembly traversed by the thread after it has passed the withdrawal rim, and the spring load urges the cut-off eye away from the imaginary thread drum axis into the area below the withdrawal rim, into which area is also moved the point at which the thread leaves the withdrawal rim during a reduction of the withdrawal tension, whereby the thread tension assists the spring force in moving the cut-off eye into a deactivating or warning position.

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US. atent Dec.30, 1975 Sheet10f2 3,928,987

US. Patent Dec. 30, 1975 Sheet 2 of2 3,928,987

THREAD SUPPLY DEVICE FOR TEXTILE MACHINES FIELD OF THE INVENTION This invention relates to a thread supply device for a textile machine and, in particular, an improved thread supply device for controlling the supply of thread to a knitting machine while permitting the maintaining of a minimum withdrawal tension in the thread.

BACKGROUND OF THE INVENTION This invention relates to a thread supply device for textile machines, in particular knitting machines, comprising a thread drum which can be set in rotation and upon which there is tangentially wound the thread issuing from a storage bobbin in order to form an intermediate supply and from which drum the thread may be unwound vertically over a withdrawal rim of the drum and through a withdrawal eye assembly which is disposed coaxially to said drum and which comprises a cut-off eye which may be pivoted transversely to the thread passage due to spring action, and further comprising a thread control element which is arranged to be stationary in the area of the path of the withdrawn thread adjacent the withdrawal rim, but which is preferably arranged to be movable out of the withdrawing path if so desired, and against which thread control element the thread laterally abuts due to the withdrawal tension during positive thread supply.

A thread supply device of this type is described in my earlier application Ser. No. 449 258, filed Mar. 8, I974. The withdrawal eye assembly in that application includes a pair of stationary withdrawal eyes in spaced relation on the imaginary drum axis between which the cut-off eye is located. If the withdrawal tension is decreased for example due to the fact that too much thread is supplied to the textile machine, due to the presence of dirt in the thread guide at the point of thread consumption or due to the fact that a knot in the thread issuing from the thread drum becomes untangled, the cut-off eye may be pivoted laterally and forms between the two stationary withdrawal eyes a thread loop which extends to the side. If the resultant movement of the cut-off eye is great enough, the cut-off is activated. In this assembly, the spring action acting on the cut-off eye must be relatively great so that the cutoff eye is capable of laterally drawing the thread unwinding from the thread drum between the two withdrawal eyes in the form of a loop in the event that the withdrawal tension is reduced. This relatively great force of the spring, however, also acts on the thread during normal positive operation of the thread supply device so that the minimum tension in the thread being supplied to the textile machine cannot be reduced as much as desired.

The invention is based on the object of designing a thread supply device of the class described at the outset such that it is possible to indicate an undesirably great reduction in the withdrawal tension, but nevertheless carry out positive thread supply with a very low withdrawal tension.

This object is accomplished in accordance with the invention in that the cut-off eye is the first eye of the withdrawal eye assembly traversed by the thread after it has passed the withdrawal rim, and that the spring load urges the cut-off eye away from the imaginary 2 thread drum axis into the area below the withdrawal rim, and into which area is also moved the point at which the thread leaves the withdrawal rim during a reduction of the withdrawal tension.

The invention avails itself of the following phenomenon: in a thread supply device of the recited class, the thread unwinding over the withdrawal rim of the thread drum abuts laterally on the thread control element during normal positive supply operation. This abutment is due to the fact that the vertically withdrawn thread attempts to travel around the withdrawal rim due to the withdrawal tension, but is prevented from doing so by the thread control element. Thus, only that amount of thread may be removed or withdrawn which is released by the rotation of the thread drum. In this way, the point at which the thread passes over the withdrawal rim is normally fixed in space and is located adjacent the thread control element. If the tension is decreased in the withdrawn thread, less thread is removed from the drum than is released due to its rotation. The rotating thread drum pulls the unwinding thread along in the direction of rotation so that the point at which the thread leaves the withdrawal rim 1 travels in the direction of drum rotation away from the thread control element along a circular path determined by the circumference of the withdrawal rim. Due to this movement, the thread unwinding from the drum attempts to pivot the cut-off eye, which it reaches first, in a lateral direction toward the location at which the displaced point of withdrawal is located due to the residual tension still present in the thread. Since the cut-off eye is urged in the same direction due to the spring force acting thereupon, the residual withdrawal tension in the thread and the spring force enhance one another. A very slight spring force is thus sufficient to indicate an inadmissible decrease in the withdrawal tension at the cut-off. The reduced spring force acting on the cut-off eye also causes reduced withdrawal tension in the thread during normal positive thread supply as well.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an inventive thread supply device in a position during normal positive thread supply and FIG. 2 shows the thread supply device according to FIG. 1 in a position during an inadmissibly high reduction in the withdrawal tension of the thread;

FIG. 3 is a diagrammatic plan view of the relationship between the thread and the cut-off eye when positioned as illustrated in FIG. 1;

FIG. 4 is a view similar to FIG. 3 but illustrating the cut-off eye positioned as shown in FIG. 2.

DETAILED DESCRIPTION In the drawing, the numeral 1 is a thread drum which is rotatably journaled in a housing 2. The housing 2 is secured to a textile machine, in particular a knitting machine, by means which are not shown in the drawing, there being a plurality of thread supply devices corresponding to the number of knitting systems being provided in the knitting machines. The drum 1 is driven via a pin wheel 3 and a perforated belt (not shown) which cooperates with the pin wheel and which is driven synchronously with the textile machine. The thread F issues from a supply bobbin (not shown), passes through a preliminary braking means 4, a disc brake 5 and a thread monitoring device 6 to be wound 3 tangentially upon the thread drum 1 which rotates in the direction indicated by the arrow P. The thread drum 1 is associated with an inclined displacement disc 7 which displaces the thread windings which are formed in axial direction along the thread drum so that an intermediate thread supply V is formed on the drum. The thread is unwound from the intermediate supply V through a braking ring 8 in vertical direction and over a lower withdrawal rim 1a of the thread drum 1. The unwinding thread F passes through a withdrawal eye assembly illustrated by the numeral 9 in FIG. 1. This consists of a stationary withdrawal eye 10, which is located on the imaginary axis A of the thread drum, and of a cut-off eye 11 which is the thread eye first reached by the unwinding thread F after leaving the withdrawal rim 1a. From the withdrawal eye 10, the thread arrives at the working station of the textile machine, for example at the thread guide element of one knitting system of a knitting machine. The withdrawal eye is journaled at the free end of a support arm 12 secured to a support rod 13 which extends outside the thread drum 1 parallel to the imaginary axis A thereof and which is mounted in the housing 2 at its other end.

Directly below the withdrawal rim la, there is provided a hook 15 which is journaled on the support rod 13 by means of a hub 14, which hook 15 can be pivoted about an axis in the plane of the drawing in the case of the illustrated embodiment from the position shown in the drawing, in which the mouth of the hook which is open toward the viewer of the drawing projects into the path of the thread F, into a position in which it does not project into the path of the unwinding thread. This pivotability serves to switch over from positive to intermittent thread supply and is not of prime importance for the present invention, nor is it essential that this be a hook. It could also be any other thread control element, for example, a rod, so long as the unwinding thread is not completely enclosed by this thread control element.

The cut-off eye 11 is positioned on a pivotal arm 16 which is urged by a spring 18 such that the cut-off eye 11 tends to pivot about an axis B, clockwise in FIG. 3, i.e., out of the plane of the drawing in FIG. 1 toward the viewer.

OPERATION The mode of operation is as follows:

The withdrawal tension in the thread section P removes the thread vertically from the bottom of the thread drum 1. The speed of withdrawal and the speed of rotation of the thread drum 1 are coordinated so that the unwinding thread F has a slight tendency to travel about the withdrawal rim 1a imagined as being stationary contrary to the direction of rotation P of the thread drum. The hook 15 however is in the path of this movement so that the location at which the thread F leaves the withdrawal rim la is normally fixed in space. This normal point of withdrawal is characterized as Ap in FIG. 1. It lies directly above the hook 15. By maintaining the point of withdrawal Ap contrary to the direction of drum rotation, only that amount of thread may be unwound from the drum 1 as is released during rotation of the drum at the point of withdrawal Ap above the hook 15. This ensures positive thread supply.

The withdrawal tension present in the unwinding thread F causes the thread to be taut between the point of withdrawal Ap and the withdrawal eye 10, which thread is indicated by a dotted line in FIG. 3.

This taut thread holds the cut-off eye 11 in the position shown in FIGS. 1 and 3 against the force of the spring 18 which acts on the eye 11. In this position, the cut-off eye 1 1 is positioned coaxially relative to the withdrawal eye 10. The thread tension force which exists in the thread segment which extends between the withdrawal point Ap and the coaxially aligned eyes 10 and 11 thus lies within a plane which passes substantially through both axes A and B. On the other hand, the spring force created by the spring 18, as acting on the arm 16, acts in a direction which is substantially perpendicular to this plane, which spring force tends to swing the eye 1 1 into its cut-off position. Accordingly, when the thread passes through its normal withdrawal point Ap and the eye 11 is in its normal position of alignment with the eye 10, the tension force in the thread thus maintains the eye 11 aligned with the eye 10 and does not assist in moving the eye 11 away from this position.

If the withdrawal tension is reduced, for example because the textile machine does not require as much thread as the supply device is supplying or because the thread is jammed somewhere along the path between the supply device and the textile machine due, for example, to dirt in the thread guide or because an already formed tangle becomes untangled between the thread supply device and the textile machine, the tendency of the unwinding thread F to travel about the withdrawal rim 1a opposite the direction of rotation P due to the withdrawal tension not only stops, but also reverses so that the thread drum 1 pulls the unwinding thread F along in the sense of rotation P. As shown in FIGS. 2 and 4, the thread F thus leaves the hook l5 and escapes laterally. The point of withdrawal, i.e. the location at which the thread F passes over the withdrawal rim 1a, moves along the withdrawal rim lain a circular path and reaches the location Ap' shown in FIGS. 2 and 4 for instance. The unwinding thread F extends between the point of withdrawal Ap and the withdrawal eye 10. The point of withdrawal Ap' is displaced along a circle defined by the withdrawal rim 1a in the same direction in which the spring 18 attempts to urge the cut-off eye 11. The residual tension in the thread F (which thread is indicated by a dotted line in FIG. 4) thus has a force component which acts in a direction which is substantially perpendicular to the arm 16 so that the thread tension thus assists the spring force in pivoting the cut-off eye 11 into the position shown in FIG. 2, in which position it deactivates the textile machine by means of a conventional switching assembly (not shown) and/or activates an indicating means 17.

The invention is not limited to the embodiment described herein. As already mentioned, the hook may be replaced by a rod or by another thread control element as long as the thread F is permitted to leave the thread control element laterally when the withdrawal tension is reduced. The cut-off eye 11 does not have to be eye-shaped in configuration. A guide element abutting on the unwinding thread laterally would also suffice. It is only essential that no other thread guide element be located between the withdrawal rim la and the cut-off eye 1 1. This would make it necessary for the cut-off eye to laterally deflect the thread in the form of a loop when the withdrawal tension decreases.

In principle, the invention may also be used on thread supply devices with stationary thread drums. In this case, a rotating winding element is provided which would have to be connected to the thread control element.- If the thread supply, becomes excessive, the unwinding thread leaves the control element in this case as well as arrives in a position in which it coacts to pivot the cut-off eye.

Although a particular preferred embodiment of the invention has been disclosed above for illustrative purposes, it will be understood that variations or modifications thereof which lie within the scope of the appended claims are fully contemplated.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a thread supply device for a textile machine, in particular a knitting machine, said thread supply device including drum means upon which a thread can be tangentially wound to form an intermediate thread storage and from which the thread can be unwound axially over a withdrawal rim associated with the drum means, a thread control member positioned adjacent the withdrawal rim of said drum means for engaging the withdrawn thread to limit the withdrawal rate of thread from said drum means substantially to the rate at which thread is wound on the drum means to thereby provide a positive thread supply, and a thread guide assembly disposed in substantial alignment with the longitudinal axis of said drum means for guiding the thread withdrawn from said drum means after it passes over the withdrawal rim, the thread guide assembly including a first thread guide element aligned with the axis of said drum means and disposed in engagement with the withdrawn thread, the thread guide assembly including a second thread guide element disposed adjacent the first thread guide element and means mounting the second thread guide element for pivotal movement substantially transversely relative to the thread passage therepast, the second thread guide element being substantially coaxially aligned with the axis of said drum means during positive thread supply, and spring means coacting with said second thread guide element for urging same transversely away from its position of alignment with the axis of said drum means, comprising the improvement wherein the withdrawn thread after passing over the withdrawal rim and the thread control member is supplied directly to the second thread guide element, said second thread guide element engaging the thread as withdrawn from the drum means prior to engagement thereof by any other part of the thread guide assembly, and said spring means normally swingably urging said second thread guide element outwardly toward an area which is substantially aligned with a part of the withdrawal rim over which the with drawn thread passes as it moves relative to the thread control member due to a reduction in the thread withdrawal tension.

2. A device according to claim 1, wherein said second thread guide element is mounted for pivotal movement about an'axis which is substantially parallel to the axis of said drum means but is spaced outwardly from the withdrawal rim.

3. A device according to claim 1, wherein said drum means is mounted for rotation about said axis. 

1. In a thread supply device for a textile machine, in particular a knitting machine, said thread supply device including drum means upon which a thread can be tangentially wound to form an intermediate thread storage and from which the thread can be unwound axially over a withdrawal rim associated with the drum means, a thread control member positioned adjacent the withdrawal rim of said drum means for engaging the withdrawn thread to limit the withdrawal rate of thread from said drum means substantially to the rate at which thread is wound on the drum means to thereby provide a positive thread supply, and a thread guide assembly disposed in substantial alignment with the longitudinal axis of said drum means for guiding the thread withdrawn from said drum means after it passes over the withdrawal rim, the thread guide assembly including a first thread guide element aligned with the axis of said drum means and disposed in engagement with the withdrawn thread, the thread guide assembly including a second thread guide element disposed adjacent the first thread guide element and means mounting the second thread guide element for pivotal movement substantially transversely relative to the thread passage therepast, the second thread guide element being substantially coaxially aligned with the axis of said drum means during positive thread supply, and spring means coacting with said second thread guide element for urging same transversely away from its position of alignment with the axis of said drum means, comprising the improvement wherein the withdrawn thread after passing over the withdrawal rim and the thread control member is supplied directly to the second thread guide element, said second thread guide element engaging the thread as withdrawn from the drum means prior to engagement thereof by any other part of the thread guide assembly, and said spring means normally swingably urging said second thread guide element outwardly toward an area which is substantially aligned with a part of the withdrawal rim over which the withdrawn thread passes as it moves relative to the thread control member due to a reduction in the thread withdrawal tension.
 2. A device according to claim 1, wherein said second thread guide element is mounted for pivotal movement about an axis which is substantially parallel to the axis of said drum means but is spaced outwardly from the withdrawal rim.
 3. A device according to claim 1, wherein said drum means is mounted for rotation about said axis. 